Cholesterol is a hydrophobic molecule found in all animals as an essential component of cell membranes and hormones and is known to be involved in other vital functions as well. Since cholesterol is present in all animal tissue, cholesterol is consumed every time food of animal origin is eaten. Although cholesterol is essential for body processes, it is not necessary for this compound to be ingested, since the liver can produce all that is needed.
Cholesterol is found and stored in blood as a fatty acid ester which is complexed with serum proteins. These cholesterol ester-protein complexes found in blood are termed lipoproteins. In this way "nature" has found a method to allow water insoluble cholesterol to become soluble in whole blood. There are two types of lipoproteins which have been identified in blood, and these two types are low density lipoproteins (LDL) and high density lipoproteins (HDL). LDL cholesterol is known to contain a high proportion of cholesterol and has been indicted as being the agent responsible for the deposition of cholesterol in artery walls. HDL cholesterol, on the other hand, is believed to transport cholesterol to the liver for removal from the blood. Thus, LDL cholesterol has been characterized as "bad" cholesterol, while HDL cholesterol has been characterized as "good" cholesterol.
A relationship has been established between total blood cholesterol (which is primarily the LDL fraction) and coronary artery disease. Guidelines have been established for adults over 20 years of age to identify risk groups associated with blood cholesterol level. These levels are as follows: &lt;200 mg/dl is desirable blood cholesterol; 200 to 239 mg/dl is borderline high blood cholesterol; &gt;240 mg/dl is considered high blood cholesterol.
Cholesterol levels can be controlled by both diet and cholesterol-lowering drugs. The key to such efforts to control cholesterol levels is to identify those individuals at risk. There has been an effort in the past several years to identify individuals with elevated cholesterol levels and initiate treatment. This effort is expected to lower mortality from coronary heart disease. A procedure whereby cholesterol levels could be easily and conveniently determined at home, therefore, would be particularly useful in the effort to lower mortality from coronary heart disease.
The following methodology includes assay strip design and performance characteristics for a non-instrumented whole blood cholesterol assay which is well-suited for home use. This type of home testing will improve the method for identification of those at risk and further reduce death from coronary heart disease.